Other forms: parliamentarians
A parliamentarian is someone who's very familiar with the rules of a legislative body, often because they're a member of it. In the U.S., a parliamentarian advises lawmakers on complex Senate and House rules.
In the 17th century, parliamentarians opposed the monarchy during the English Civil War; in Britain today, a parliamentarian is simply a member of parliament, the U.K. government. United States parliamentarians, experts in the rules of the legislature, are appointed to the House and Senate by the majority party. Their job is to answer any procedural questions and offer nonpartisan advice. Parliamentarian is from parliament, "assembly," and its Latin root, meaning "to speak."